Variable capacitor array, variable capacitor array device and circuit module

Abstract

The invention relates to a variable capacitor array which has excellent controllability on a capacitance value and has variable and high tunability. The variable capacitor array includes a first variable capacitor (C 1 ) having a capacitance which is varied according to application of voltage; a first terminal (O 1 ) connected to one side of the first variable capacitor; a second variable capacitor (C 2 ) having a capacitance which is varied by application of voltage; a second terminal (O 2 ) connected to one side of the second variable capacitor; and a third terminal (I) connected to both of the other side of the first variable capacitor and the other side of the second variable capacitor, wherein a state can be selected by switching between at least two selection states among three selection states of a first selection state that the first terminal (O 1 ) and the third terminal (I) are selected, a second selection state that the second terminal (O 2 ) and the third terminal (I) are selected, and a third selection state that the first selection state and the second selection state are selected simultaneously.

1. A variable capacitor array comprising:
 a first variable capacitor comprising a first dielectric layer having a first dielectric constant which is varied by application of a voltage, and a pair of electrodes holding the first dielectric layer therebetween; 
 a second variable capacitor comprising a second dielectric layer having a second dielectric constant which is varied by application of a voltage, and a pair of electrodes holding the second dielectric layer therebetween; 
 a first terminal connected to one electrode of the pair of electrodes of the first variable capacitor; 
 a second terminal connected to one electrode of the pair of electrodes of the second variable capacitor; and 
 a third terminal connected to both of another electrode of the pair of electrodes of the first variable capacitor and another electrode of the pair of electrodes of the second variable capacitor, 
 wherein a selection state can be selected by switching between at least two selection states among three selection states of a first selection state that the first terminal and the third terminal are selected, a second selection state that the second terminal and the third terminal are selected, and a third selection state that the first selection state and the second selection state are selected simultaneously, 
 wherein a variable capacitance range in the first selection state and a variable capacitance range in the second selection state partially overlap with each other and/or the variable capacitance range in the first selection state and a variable capacitance range in the third selection state partially overlap with each other, the variable capacitance range in the second selection state and the variable capacitance range in the third selection state being separated from each other. 
 
     
     
       2. The variable capacitor array of  claim 1 , wherein capacitance values of the first variable capacitor and the second variable capacitor satisfy all the following expressions (1) and (2):
     C 1(0)≧ C 2(0)  (1)
 
     C 1(0)≧ C 1( V )+ C 2( V )  (2)
 
 
       where C 1 ( 0 ) and C 1 (V) respectively represent capacitances of the first variable capacitor before and after voltage application, and C 2 ( 0 ) and C 2 (V) respectively represent capacitances of the second variable capacitor before and after voltage application. 
     
     
       3. The variable capacitor array of  claim 1 , wherein capacitance values of the first variable capacitor and the second variable capacitor satisfy all the following expressions (3) and (4):
     C 1(0)≧ C 2(0)  (3)
 
     C 2(0)≧ C 1( V )  (4)
 
 where C 1 ( 0 ) and C 1 (V) respectively represent capacitances of the first variable capacitor before and after voltage application, and C 2 ( 0 ) and C 2 (V) respectively represent capacitances of the second variable capacitor before and after voltage application. 
 
     
     
       4. The variable capacitor array of  claim 1 , wherein capacitance values of the first variable capacitor and the second variable capacitor satisfy all the following expressions (5) to (7):
     C 1(0)≧ C 2(0)  (5)
 
     C 1(0)≧ C 1( V )+ C 2( V )  (6)
 
     C 2(0)≧ C 1( V )  (7)
 
 
       where C 1 ( 0 ) and Cl(V) respectively represent capacitances of the first variable capacitor before and after voltage application, and C 2 ( 0 ) and C 2 (V) respectively represent capacitances of the second variable capacitor before and after voltage application. 
     
     
       5. The variable capacitor array of  claim 1 , wherein at least one of the first and second variable capacitors comprises a variable capacitance element group including N pieces (where N is a natural number) of variable capacitance elements connected in series, and a group of first separate bias lines and a group of second separate bias lines which are alternately connected to both ends of the variable capacitance element group and between adjacent pieces of the variable capacitance elements, in one array direction of the variable capacitance elements. 
     
     
       6. The variable capacitor array of  claim 5 , further comprising:
 a first bias terminal to which the group of first separate bias lines is connected in common; and 
 a second bias terminal to which the group of second separate bias lines is connected in common. 
 
     
     
       7. The variable capacitor array of  claim 5 , wherein the variable capacitance element group comprises an odd number of the variable capacitance elements connected to each other, and the group of first separate bias lines is connected in common and the group of second separate bias lines is connected in common. 
     
     
       8. A variable capacitor array device comprising:
 the variable capacitor array of  claim 7 ; 
 a switching element for selecting a state by switching between at least two selection states among the three selection states; and 
 a fourth terminal to which at least one of the first and second terminals are connected in common by way of the switching element. 
 
     
     
       9. The variable capacitor array device of  claim 8 , wherein the switching element is a PIN diode. 
     
     
       10. The variable capacitor array device of  claim 8 , wherein the switching element comprises a MEMS element. 
     
     
       11. A circuit module comprising:
 the variable capacitor array device of  claim 10 , wherein the third terminal and the fourth terminal serve as input and output terminals. 
 
     
     
       12. The variable capacitor array of  claim 1 ,
 wherein a capacitance in the selection state, which is selected by switching between the first selection state and the second selection state, continuously changes, 
 wherein a capacitance in the selection state, which is selected by switching between the first selection state and the third selection state, continuously changes. 
 
     
     
       13. The variable capacitor array of  claim 1 , wherein a lower limit of the variable capacitance range in the first selection state is equal to an upper limit of the variable capacitance range in the second selection state and/or an upper limit of the variable capacitance range in the first selection state is equal to a lower limit of the variable capacitance range in the third selection state. 
     
     
       14. The variable capacitor array of  claim 1 , wherein the capacitance continuously changes by switching a voltage applied state or not applied state which is based on switching between the two selection states.